Page 1 of 3 123 LastLast
Results 1 to 15 of 33

Thread: Spider in steady fingers question..

  1. #1
    Join Date
    Apr 2003
    Posts
    45

    Spider in steady fingers question..

    Hi all!

    Been toying with the idea of running a spider in the steady for chambering/threading and wanted to pass it by more intelligent minds than mine : )
    I believe this has been done before, just not a ton of info on it.
    I'm thinking of making a spider out of 12L14 around 2" OD and 1" long. It will be perfectly round on the OD with one end having 4 brass set screws and the other smooth. The fingers will obviously run on the smooth end. I'll ream a 1.5" hole through the center. The idea is to put it in the fingers of the steady with the chamber end of barrel through it. A 4-jaw will drive the muzzle end. Unless I am missing something I should be able to indicate the chamber for radial runout using the set screws in this spider, and indicate the axial with the 4 jaw. It's basically the same as using a spider on the backend of the spindle except in reverse - still there exists 2 adjustable points of contact. I think this would be useful for those of us that have lathes that do no have sufficient hole through spindle, or headstocks that are very long where we don't want to deal with barrel extensions. It would allow for more precise indication of the barrel in the steady setup vs just using centers, which as we all know is no guarantee the bore is running true.

    Am I missing something here or is this a sound idea?

    thanks for any advice!

  2. #2
    Join Date
    Jul 2016
    Location
    Surprise, AZ
    Posts
    421

    IIRC - which is always questionable...

    Quote Originally Posted by skipkh View Post
    Hi all!

    Been toying with the idea of running a spider in the steady for chambering/threading and wanted to pass it by more intelligent minds than mine : )
    I believe this has been done before, just not a ton of info on it.
    I'm thinking of making a spider out of 12L14 around 2" OD and 1" long. It will be perfectly round on the OD with one end having 4 brass set screws and the other smooth. The fingers will obviously run on the smooth end. I'll ream a 1.5" hole through the center. The idea is to put it in the fingers of the steady with the chamber end of barrel through it. A 4-jaw will drive the muzzle end. Unless I am missing something I should be able to indicate the chamber for radial runout using the set screws in this spider, and indicate the axial with the 4 jaw. It's basically the same as using a spider on the backend of the spindle except in reverse - still there exists 2 adjustable points of contact. I think this would be useful for those of us that have lathes that do no have sufficient hole through spindle, or headstocks that are very long where we don't want to deal with barrel extensions. It would allow for more precise indication of the barrel in the steady setup vs just using centers, which as we all know is no guarantee the bore is running true.

    Am I missing something here or is this a sound idea?

    thanks for any advice!
    I think Steve Acker ("Gunsmith Machinist" from the Village Press Mags - Home Shop Machinist and Machinist's Workshop) did something very similar in a video they produced. Never tried it myself. Seems workable, in conjunction with wires or whatever to allow the chucked end to move axially without undue stress.

    GsT

  3. #3
    Join Date
    Apr 2003
    Posts
    45
    thanks for the lead! I'll try to hunt down the video.
    Yep - I use 4g copper wire in the 4-jaw when I chamber in the headstock, so planning the same in this setup.

  4. #4
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,941
    skipkh,

    I've found that pivoting the barrel exactly on the leade of the proposed chamber throat is an incredible timesaver so may I suggest that whatever you make, that it have this capacity.

  5. #5
    Join Date
    Apr 2003
    Posts
    45
    Quote Originally Posted by alinwa View Post
    skipkh,

    I've found that pivoting the barrel exactly on the leade of the proposed chamber throat is an incredible timesaver so may I suggest that whatever you make, that it have this capacity.

    That's an excellent tip! I can place the set screws where the proposed leade would be in this design very conveniently. I can also see two pivot options..
    1) put a slight crown on the race of the spider which would facilitate pivot.
    2) Shape the ends of the set screws as a ball, which would also serve to facilitate pivot.

    A few of the advantages of this design is it's lathe agnostic. With a spindle spider I have to sort out an attachment method for each machine. This solution would fit any steady rest.
    Another advantage is as you mentioned. I can move the steady to wherever I need it relative to the chamber... something not so convenient when held in the chuck. The obvious concern is rigidity, however I think it is ok. I will test and see pretty quickly.

  6. #6
    Join Date
    Oct 2004
    Location
    Brisbane Australia
    Posts
    161
    Quote Originally Posted by alinwa View Post
    skipkh,

    I've found that pivoting the barrel exactly on the leade of the proposed chamber throat is an incredible timesaver so may I suggest that whatever you make, that it have this capacity.
    Al, you betcha! It's a massive time saver!! Yet i've almost never heard the "Internet" gunsmith gurus even mention it.
    It's something i have always done when fitting barrels as it does indeed save a LOT of time dialing one in..

    Cheers
    Lee

  7. #7
    Join Date
    Feb 2003
    Location
    Poetry, Tex.
    Posts
    7,128
    So, how do you indicate the bore in the muzzle end that is in the 4 jaw. Maybe you're using the gordy method?
    Last edited by Butch Lambert; 05-13-2022 at 03:31 PM.

  8. #8
    Join Date
    Jan 2009
    Location
    Ca.
    Posts
    994
    How would one then get all three points to be running true each other. The muzzle, the area in front of the throat and the chamber. This has been my own approach and it came from Jackie Schmidt sharing his own personal method.

  9. #9
    Join Date
    Apr 2003
    Posts
    45
    Quote Originally Posted by Butch Lambert View Post
    So, how do you indicate the bore in the breech end that is in the 4 jaw. Maybe you're using the gordy method?
    Hi Butch!

    Glad you chimed in : )

    Muzzle end goes in the 4-jaw. Breech end rides in the spider located in the fingers of the steady. Indicator rod (or DTI with long feeler) goes in the bore. set screws on spider in the steady are used to dial in the bore for runout. 4-jaw (with copper wire between jaws and muzzle end of barrel) are used to dial in the bore for axial alignment. Basically the roles of the spider and the chuck are reversed regarding what they adjust for vs the typical chamber through headstock method.

  10. #10
    Join Date
    Apr 2003
    Posts
    45
    Quote Originally Posted by Louis.J View Post
    How would one then get all three points to be running true each other. The muzzle, the area in front of the throat and the chamber. This has been my own approach and it came from Jackie Schmidt sharing his own personal method.
    It's been my experience that this is not typically achievable. The bore isn't straight on most barrels. If you dial in the muzzle then the chamber end will be out and vice versa. In chambering, at least in my experience, I ignore the muzzle when setting up to chamber. Where the leade is going to be needs to have no runout - ie; in line with the center of the lathe. The chamber area of the barrel needs to have no axial runout. Those are the two areas of concern. See my reply to Butch as to how this is accomplished. Basically it's the same as a spider on the rear of the spindle but the roles of the chuck and the spider are reversed with respect to what aspect they adjust for.

  11. #11
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,941
    yo skipkh..... I started a youtube channel just to illustrate my method of making perfectly aligned and perfectly identical chambers..... and to prove that I can unscrew a barrel chambered yrs prior and set 'er BACK in the lathe to the same index...blind...and included is my way of affixing/swiveling/driving/holding which I'm perty psyched about....... how I make my soft swiveling pads. Dunno if this applies to what you're doing but it is a slick way to grip tapered surfaces, I'd use this at least on the drive end if fear of marring is a thing.

    Mfgr of holding stuff starts around 5.00 in the vid

    https://www.youtube.com/watch?v=zzq_uLa0-NE

  12. #12
    Join Date
    Feb 2003
    Location
    Poetry, Tex.
    Posts
    7,128
    Quote Originally Posted by skipkh View Post
    It's been my experience that this is not typically achievable. The bore isn't straight on most barrels. If you dial in the muzzle then the chamber end will be out and vice versa. In chambering, at least in my experience, I ignore the muzzle when setting up to chamber. Where the leade is going to be needs to have no runout - ie; in line with the center of the lathe. The chamber area of the barrel needs to have no axial runout. Those are the two areas of concern. See my reply to Butch as to how this is accomplished. Basically it's the same as a spider on the rear of the spindle but the roles of the chuck and the spider are reversed with respect to what aspect they adjust for.
    Sorry, I messed up, but corrected it. You are using the gordy method.
    Oh well.

  13. #13
    Join Date
    Jan 2009
    Location
    Ca.
    Posts
    994
    This method of chambering is based on the premis that you can only get the ID of a barrel dead true in two spots. So, you establish those two spots, (the muzzle and where the throat will be established), and single point bore the third spot, i.e. the chamber, dead true with these. You don't worry about everything in between.

  14. #14
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,941
    Quote Originally Posted by Louis.J View Post
    This method of chambering is based on the premis that you can only get the ID of a barrel dead true in two spots. So, you establish those two spots, (the muzzle and where the throat will be established), and single point bore the third spot, i.e. the chamber, dead true with these. You don't worry about everything in between.
    Louis. you've described the standard method of chambering around here..... ie to align muzzle and throat. 99.9% of all accuracy-minded and Bench Rest Gunsmiths do it this way.

    "Gordying" is completely different.

    On that subject, much as I distrust 'straight' barrels I've had a slew of them lately! 8 out of 12 have shown less than a thou of runout. The way I do them I do all my setup work inboard at the 4-jaw ......then last thing, just as I'm locking down the outboard or spider end I slip a tight-fitting reamer bushing up past the lapping bell (I've a machined brass hook to get it back out) to find the runout.

  15. #15
    Join Date
    Sep 2003
    Location
    Oriental, NC
    Posts
    1,050
    Al,
    I've seen a custom built steady using a high grade bearing instead of fingers with a spider built in. I seem to recall it was used for shotgun choke work. Made sense to me at the time. Would be fine for barrel work.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •